Probing the E4 State of Mo Nitrogenase using Fe,Mo Kalpha High Energy Resolution Fluorescence Detected X-ray Absorption and Fe Valence-to-Co

Fixation of atmospheric nitrogen into bioavailable forms such as ammonia is critical for life on earth. Beyond the need for ammonia in fertilizer production, this hydrogen-rich molecule is an attractive green energy storage intermediate. The majority of ammonia is produced by nitrogenases, which serve as the exclusive biological route to nitrogen fixation. Therefore, understanding how these enzymes are capable of performing this exceptionally difficult reaction is important for the development of competent energy efficient catalysts. We intend to investigate the nature of the catalytic intermediates of nitrogenase immediately prior-to and following N2 binding using a combination of Fe valence-to-core X-ray emission spectroscopy along with Fe and Mo Kalpha HERFD XAS, which will provide significant insight into the nature of the Femoco-N2 interaction and thus biological nitrogen fixation.